Power Requirements for 7900GT/7900GTX

[RussianSensation]

NVIDIA recommend a 350W-400W power supply (22-26A on the 12V rail) for the GeForce 7900 GTX, while a 300W-350W power supply is recommend for the 7800 GT (20-23A on the 12V rail).

I hope this helps to anyone concerned with their older PSUs. A PSU I can recommend is ENERMAX EG651P-VE FM(24P) 550W It has 36A on 12V rail, and it has been shown several times that 1 strong 12V rail is better than dual rails for SLI cards.

Cheers.

EDIT:

Ultra High-End SLI PC - with dual core cpu
You must have a power supply that can provide a minimum of +12V @ 22A of dedicated power for the two graphics cards. Of this 22A requirement, +12V @ 5.5A must be available to each of the two PCI Express 6-pin auxiliary power supply connectors. The remaining 11A must be supplied to the motherboard for dedicated graphics card use.

High-End SLI PC*: FX-57, nForce4 x16 SLI, 2 HDD Raid 0, 2GB RAM, 2 optical drives, one PCI sound card
Minimum of 500-600W Power Supply with a minimum of +12V @ 30A for all PC components.

Mid-Range SLI PC*: ie. A64 4000+, 1 HDD, nForce 4SLi, 1GB RAM, 2 optical drives, one PCI sound card
Minimum of 450-500W Power Supply with a minimum of +12V @ 26A for all PC components.

Low-End SLI PC*:
Minimum of 400-450W Power Supply with a minimum of +12V @ 22A for all PC components.

Source: Firingsquad

Full System Load
TechReport - Power Consumption @ Load - includes SLI
Anandtech - Single Cards

 

[nib95]

I need to know this too, dont mean to jack your thread sensation, but I have to ask *shy face*.
Will a Enermax 500w be enough to power my SLI 7900 GT OC'd and Opteron 170 @ 2.7ghz?

 

[Extelleron]

7900GT requires less power than a 7800GTX, 7900GTX takes up about the same, so I'd say 400W should be good enough, as long as its a quality PSU, which is more important than the wattage. You could have a cheap 800W PSU that wouldnt run the 7900GT because wattage matters very little in the end.

 

[firewolfsm]

yes, check the extreme psu calculator (search google for those words)

 

[RussianSensation]

Originally posted by: nib95
I need to know this too, dont mean to jack your thread sensation, but I have to ask *shy face*.
Will a Enermax 500w be enough to power my SLI 7900 GT OC'd and Opteron 170 @ 2.7ghz?

Hey. I think as long as you have 1 single rail above 26A or 2 dual rails at 16A or higher you'll be fine.

Check out power consumption graph I added as well at load. Seems your system could even handle 7900GTX SLI.

 

[nib95]

Originally posted by: RussianSensation

Originally posted by: nib95
I need to know this too, dont mean to jack your thread sensation, but I have to ask *shy face*.
Will a Enermax 500w be enough to power my SLI 7900 GT OC'd and Opteron 170 @ 2.7ghz?

Hey. I think as long as you have 1 single rail above 26A or 2 dual rails at 16A or higher you'll be fine.

Check out power consumption graph I added as well at load. Seems your system could even handle 7900GTX SLI.

Thats cool, I belive both of the rails in the enermax Liberty are over 20a so I'm good to go.

 

[moonboy403]

the 7900 gtx actually has a slight decrease in terms of power consumption (comparing 512 gtx)

so it's a good sign!